C8 - Host Microorganisms Interactions (Part 2) Flashcards
1
Q
HOST RESISTANCE
A
Physical Barriers
Macrophages
2
Q
Physical Barriers
A
a. Healthy, Intact Skin
b. Cleansing Mechanisms
c. Antimicrobial Substances
d. Indigenous Microbial Flora
e. Phagocytosis
3
Q
→ primary mechanical barrier to infection
A
Healthy, Intact Skin
4
Q
→has substantial numbers of microbial flora that contribute to a low pH, compete for nutrients, and produce bactericidal substances addition
A
Healthy, Intact Skin
5
Q
→ ensures that relatively few organisms can survive and prosper in the acid environment
A
low pH resulting from long-chain fatty acids secreted by sebaceous glands
6
Q
Spp capable of penetrating normal, healthy skin
A
Leptospira spp., Francisella tularensis, Treponema spp
7
Q
Mechanism of urethral opening as a barrier
A
Stricture
8
Q
This action allows the urethra to be less susceptible to microorganism growth
A
urination
9
Q
Found in the cervical opening that acts as a barrier for microorganism
A
thick mucus plug
10
Q
What natural process involves the shedding of the skin surface to remove potential pathogens?
A
Desquamation
11
Q
What two antimicrobial components are found in tears?
A
IgA and lysozyme
12
Q
How does the respiratory tract help remove trapped microbes?
A
Mucus traps particles and sweeps them to the oropharynx.
13
Q
What type of epithelium lines the trachea and aids in clearing particles upward?
A
Ciliated epithelium
14
Q
Which reflex helps expel potentially infected agents from the respiratory system?
A
Cough-sneeze reflex
15
Q
What two mechanisms in the gastrointestinal tract prevent organisms from attaching to the intestinal epithelium?
A
Mucous secretions and peristalsis
16
Q
What cleansing action in the genitourinary tract helps prevent infection?
A
Voiding urine
17
Q
What characteristic of the vagina inhibits colonization by transient organisms?
A
Acidity
18
Q
Cleansing Mechanisms of the body
A
Desquamation
IgA and lysozyme in tears
Mucus in RT
Ciliated epithelium in trachea
Cough-sneeze reflex
Mucous secretions and peristalsis of the GI tract
Voiding urine
Acidity of vagina
19
Q
Antimicrobial Substances
A
Lysozyme
Secretory IgA
β-lysins
Interferon
20
Q
→low-molecular-weight (approximately 20,000 D) enzyme that hydrolyzes the peptidoglycan layer of bacterial cell walls
A
Lysozyme
21
Q
Lysozyme found in
A
serum,
tissue fluids,
tears,
breast milk,
saliva, and
sweat
22
Q
→serve as opsonins, fix complement and neutralize the infecting
organism
A
Secretory IgA
23
Q
Secretory IgA →found in
A
mucous secretions of the
respiratory,
genital, and
digestive tracts
24
Q
Secretory IgA serve as
A
opsonins
25
→low-molecular-weight cationic proteins in serum
→lethal against gram-positive bacteria and are released from platelets during coagulation
β-lysins
26
→inhibits proliferation of viruses
Interferon
27
→compete with pathogens for nutrients and space
Indigenous Microbial Flora
28
→substances that inhibit the growth of closely related bacteria
Bacteriocins
29
→process by which phagocytes engulf and dispose of microorganisms and cell debris
Phagocytosis
30
necessary for the killing and digestion of the engulfed particles
Lysosomes
31
Lysosomes [enumerate]
myeloperoxidase,
proteases,
cathepsin,
lactoferrin,
lysozyme, and
elastase
32
→has receptors on the cell membrane for some complement components that stimulate cell motion, the metabolic burst, and secretion of the lysosome contents into a phagosome
PMN - polymorphonuclear leukocyte
33
PMN circulating half life hours
2-7 hours
34
PMN may migrate to the tissues where their half life is
less than a week
35
→circulate as monocytes for 1 to 2 days and then migrate through the blood vessel walls into the tissues and reside in specific tissues as part of the MONONUCLEAR PHAGOCYTE SYSTEM
Macrophages
36
Macrophages are part of the [system]
MONONUCLEAR PHAGOCYTE SYSTEM
37
→widely distributed in the body and play a central role in specific immunity and nonspecific phagocytosis
Macrophages
38
Chemotaxis two types
Diapedesis
Chemotaxis
39
→ movement of the neutrophils between the endothelial cells of the blood vessels into the tissues
DIAPEDESIS
40
→directed migration of PMNs into the area of infection
CHEMOTAXIS
41
→facilitated by the binding of specific antibodies to the microorganism
Attachment
42
→coating of the bacterium with antibody or complement components results in enhanced phagocytosis by the PMN
OPSONIZATION
43
Neutrophils have membrane receptors for?
Fc region of
IgG1
IgG3
C3b component of complement
44
Which antibody classes can bind to organisms to initiate opsonization?
IgG1 or IgG3
45
What happens when the antibody response is insufficient for opsonization?
Complement is fixed on the surface of the organism
46
Which pathway can be activated by endotoxins or polysaccharides for opsonization?
Alternative complement pathway
47
✓Cell membrane of the phagocytic cell invaginates and surrounds the attached particle
Ingestion
48
In Ingestion ✓Particle is taken into the cytoplasm and enclosed within a
vacuole called a
PHAGOSOME
49
✓Phagosome fuses with lysosomes
PHAGOLYSOSOME
50
Lysosomes release their contents into the phagosome
DEGRANULATION
51
Ingestion included enzymes
proteases,
lipases,
RNase,
DNase,
peroxidase, and
acid phosphatase
52
→phagocytosis of a particle triggers a significant increase in the metabolic activity of the neutrophil or macrophage
Metabolic or Respiratory Burst
53
Killing / Metabolic or Respiratory Burst increases in
glycolysis
54
→body’s response to injury or foreign
body
Inflammation
55
→hallmark of inflammation:
accumulation of large numbers of
phagocytic cells
56
→leukocytes release mediators or
cause other cell types to release which cause ______________ as a result of greater blood flow, edema from an increase in vascular permeability, and
continued phagocyte accumulation,
resulting in ____________
erythema
pus
57
CARDINAL SIGNS OF INFLAMMATION
SWELLING,
REDNESS,
HEAT,
PAIN,
LOSS OF FUNCTION
58
Chemical Mediatiors of Inflammation:
✓Histamine
✓Kinins
✓Leukotrienes
✓Prostaglandins
✓Acute phase reactants
✓Cytokines
59
✓Acute phase reactants examples
CRP,
Serum amyloid A,
antitrypsin,
fibrinogen
60
✓Cytokines that mediate inflammation
IL-1,
IL-6,
TNF-α,
IFN-γ,
IL-2
61
→mechanism whereby the body is able to protect itself from invasion by disease causing organisms
Immunity
62
→consists of numerous cells and protein molecules that are responsible for recognizing and removing these foreign substances
Immune system
63
Immune system Divided into two broad categories
Innate or Natural immunity
Adaptive or Specific
64
little or no specificity immune system
Innate or Natural immunity
65
highly specialized immune system
Adaptive or Specific
66
Cells of the immune system
B Lymphocytes (B Cells)
T Lymphocytes (T Cells)
Natural Killer Cells (NK Cells)
67
B Lymphocytes (B Cells) Location
Lymphoid tissues (lymph nodes, spleen, gut- associated lymphoid tissue, tonsils)
68
B Lymphocytes (B Cells) Function
Antibody-producing cells
69
B Lymphocytes (B Cells) Subtypes
B lymphocytes
B-memory cells
Plasma cells
70
Cells waiting to be stimulated by an antigen
B lymphocytes
71
Activated B lymphocytes that secrete antibody in response to an antigen
Plasma cells
72
Long-lived cells preprogrammed to antigen for subsequent exposure
B-memory cells
73
T Lymphocytes (T Cells) Location
Circulate and reside in lymphoid tissues (lymph nodes, spleen, gut-associated lymphoid tissue, tonsils)
74
T Lymphocytes (T Cells) Subtypes:
Helper T cells
Cytotoxic T cells
Suppressor T cells
75
Interact with B cells to facilitate antibody production
Helper T cells
76
Recognize and destroy host cells that have been invaded by microorganisms
Cytotoxic T cells
77
Mediate regulatory responses within the immune system
Suppressor T cells
78
Similar to that of cytotoxic T cells; however do not require the presence of an antigen to stimulate function
Natural Killer Cells
79
Immediate response to the pathogen that does not confer long lasting protective immunity
INNATE, OR NATURAL,
NONSPECIFIC IMMUNITY
80
INNATE, OR NATURAL,
NONSPECIFIC IMMUNITY examples
Physical and chemical barriers
Blood proteins
phagocytosis
81
Blood proteins that act as
mediators of infection
Cytokines,
Complement
82
→capable of being specific for distinct molecules, responding in particular ways to different types of foreign substances and developing memory, which allows for a more vigorous response to repeated exposures to the same foreign invader
ADAPTIVE, OR SPECIFIC IMMUNITY
83
2 types of ADAPTIVE, OR SPECIFIC IMMUNITY
Humoral or Cellular Immune Response
84
major constituents of the adaptive or specific immune response
Lymphocytes and Antibodies
85
able to remember each time it encounters a particular foreign antigen
Immunologic Memory
86
→Antibody mediated
. HUMORAL IMMUNE RESPONSE
87
Immunoglobulin G (IgG) percent of the total serum immunoglobulin pool
→70% to 75%
88
Immunoglobulin G (IgG) halflife in serum
3 to 4 weeks
89
→cross the maternal placenta to the
fetus
→ passive immunity for newborns,
neutralization of viruses and exotoxin;
responds best to protein antigens, mainly involved in secondary (anamnestic) immune response
Immunoglobulin G (IgG)
90
→ cannot cross the placenta
→consists of five basic subunits—each composed of two heavy chains and two light chains (similar to an IgG molecule) and linked to another polypeptide chain (J chain) by disulfide bonds
→endotoxin neutralization, bacterial agglutination, complementmediated bacteriolysis, strong opsonization ability; responds best to polysaccharide antigens, mainly involved in primary immune response
Immunoglobulin M (IgM)
91
Immunoglobulin M (IgM) percent of igms
10%-15%
92
Immunoglobulin M (IgM) half-life in serum
5 days
93
→predominant immunoglobulin class in certain body secretions, such as saliva, tears, and intestinal secretions
→ prevention of bacterial and viral invasion of mucous membranes through interference with adherence of
microorganism to site; found in tears, milk, saliva, and respiratory and GI secretions
Immunoglobulin A (IgA)
94
Immunoglobulin A (IgA) percent
15% to 20%
95
IgA occurs when
two subunits (each similar to an IgG molecule) linked together by a J chain
96
contains a secretory component that stabilizes the molecule
Secretory IgA
97
→increase during infection by numerous parasites and may play a
role in eliminating these infectious agents from the host
→major role in allergic response
Immunoglobulin E (IgE)
98
→little is known; may serve as a B-cell receptor or play a role in autoallergic diseases
Immunoglobulin D (IgD)
99
relatively rapid appearance of IgM antibodies
Primary immune response
100
Antibody Responses
Primary and Secondary
101
→rapid increase in IgG antibody associated with higher levels, a prolonged elevation, and a more
gradual decline
Secondary or Anamnestic immune response
102
→based on the action of specific kinds of T-lymphocytes that directly attack the cells that are infected with virus, parasites, cancer cells or transplanted cells
CELL-MEDIATED IMMUNE RESPONSE
103
→ primary effector cell in cell-mediated immunity
T Lymphocyte
104
→low-molecular-weight proteins resulting from antigen binding, activation, cell division, and differentiation of the T cell
Lymphokines
105
Mechanisms by Which Microbes May Overcome Host Defenses
a. Bringing about tolerance
b. Immunosuppression
c. Change in the appropriate target for the immune response
d. Antigenic variation
106
inability to induce an immune response to a microbial antigen
Tolerance
107
Antigenic variation example
Borrelia recurrentis
108
✓Most pathogen are acquired from
external sources
109
Pathogens usually exit the infected patient most frequently from the
respiratory tract and gastrointestinal
tract
110
transmission to the new host usually occurs via
airborne respiratory droplets or fecal contamination of food and water
111
Four (4) important portals of entry for pathogenic organisms
GIT, GUT, respiratory tract, integumentary system
112
Mucous membranes of the GIT, GUT, repiratory tract and conjunctiva
DISEASES
conjunctivitis, trachoma, ophthalmia
neonatorum
113
punctures, injections, bites, cuts, wounds, surgery, and splitting of the skin or mucus membrane due to swelling or drying
✓Parenteral route
114
some organisms have many portals of entry
(Yersinia and B. anthracis)
115
ROUTES OF TRANSMISSION
1. Airborne Transmission
2. Transmission by Food and Water
3. Close Contact
4. Cuts and Bites
5. Arthropods
6. Zoonoses
116
Respiratory Spread
→ common
→aerosolized by coughing, sneezing, and talking
Airborne Transmission
117
—inhalation of infectious particles in liquid droplet dxs
TB,
Brucellosis,
Tularemia,
Legionellosis and
Plague
118
→residue from the evaporation of fluid from larger droplets and are light enough to remain airborne for long periods
Droplet Nuclei
119
→infection occurs via the fecal-oral route
Transmission by Food and Water
120
Transmission by Food and Water spp
Enterotoxigenic E. coli (ETEC)
Vibrio cholera
121
Enterotoxigenic E. coli is the common cause of
TRAVELER’S DIARRHEA
122
→enterotoxin that causes the outpouring of fluid from the cells into the lumen of the intestine
Vibrio cholera
123
Preformed toxins [spp] [fecal oral route]
Clostridium botulinum,
Bacillus cereus, and
S. aureus
124
→passage of organisms by salivary, skin, and genital contact
Close Contact
125
→infection by the mouth flora
Cuts and Bites
126
→dog-bite and cat-bite infections
Pasteurella multocida
127
→tick, flea, or mite bite
Arthropods
128
Arthropods dxs
→relapsing fever,
plague,
Rocky Mountain spotted fever,
Lyme disease,
typhus
129
→depends on contact with animals or animal products
→arthropod vectors (plague), contact with secretions (brucellosis), and contact with animal carcasses and products (tularemia, listeriosis)
Zoonoses
130
Respiratory Tract pathogens
Streptococcus pneumoniae
Neisseria meningitides
Haemophilus influenzae
Mycobacterium tuberculosis
Bordetella pertussis
Salmonella typhi
Salmonella enteric
Vibrio cholera
Brucella spp
131
Streptococcus pneumoniae disease
Pneumonia
132
Neisseria meningitides disease
Meningitis
(meningococcemia)
133
Haemophilus influenzae disease
Meningitis
134
Mycobacterium tuberculosis disease
Tuberculosis
135
Bordetella pertussis disease
Pertussis (Whooping cough)
136
Salmonella typhi disease
Typhoid fever
137
Salmonella enteric disease
Salmonellosis
138
Vibrio cholera disease
cholera
139
Brucella spp. disease
Brucellosis (Undulant
fever)
140
Skin (Integumentary System), Parenteral pathogens
Clostridium perfringens
Rickettsia rickettsii
141
Clostridium perfringens disease
Gas gangrene
142
Rickettsia rickettsii disease
Rocky Mountain Spotted
Fever
143
Numbers of Invading Microbes
✓ID50
✓LD50
144
→compare relative virulence under experimental conditions; it is not an absolute value
✓ID50 (Infectious Dose for 50% of a sample population)
145
→potency of a toxin
✓LD50 (Lethal Dose for 50% of a sample population)
146
✓ID50 B. anthracis Cutaneous
10-50 endospores
147
✓ID50 B. anthracis Inhalation
10k-20k endospores
148
✓ID50 B. anthracis Gastrointestinal
250k-1M endospores
149
✓ID50 V. cholerae
108 cells (decreased upon neutralization of stomach acidity or administration of bicarbonates)
150
LD50 Botulinum toxin
0.03 ng/kg
151
LD50 Shiga toxin
250 ng/kg
152
LD50 Staphylococcal enterotoxin
1350 ng/kg
153
Host-microorganism interactions path
Encounter and entry
Colonization and entry
Invasion and dissemination
Outcome
154
Corresponding infection-disease stages
Incubation stage
Prodromal stage
Clinical stage
Stage of decline
Convalescent stage
155
Pathogen encounters and colonizes host surface
Encounter and entry
156
Pathogen multiplies and breaches host surface defenses
Colonization and entry
157
Pathogen invades deeper tissues and disseminates, encounters inflammatory and immune responses
Invasion and dissemination
158
Pathogen completes cycle by [outcomes]
Leaves host
Destroys host
Remains in latent state
Is destroyed by host
159
[stage] No signs or symptoms
Incubation stage
160
[stage] First signs and symptoms, pathogen may be highly communicable
Prodromal stage
161
[stage] Peak of characteristic signs and symptoms of infection or disease
Clinical stage
162
[stage] Condition of host deteriorates possibly to death or signs and symptoms begin to subside as host condition improves
Stage of decline
